Ionic 3 Set notification permission on toggle button

I need to know how can i use notification permission in ionic app on toggle button. I want when user turn off the toggle so user cant get FCM Push notification if toggle is on then the user can get notification. I try to use local storage when user turn off toggle i set the toggle false in localstoreage so when the user open app again the toggle button is off .

  <ion-item>
    <ion-toggle [(ngModel)]="isToggled" (ionChange)="notify()" item-start checked="true" ></ion-toggle>
        <ion-label item-end style="text-align: right;">تلقي الاشعارات
</ion-label>
  </ion-item>

.ts

  constructor(private nativeStorage: NativeStorage, private push: Push, public platform: Platform, private fcm: FCM,  public statusBar: StatusBar, public splashScreen: SplashScreen) {


    this.initializeApp();

  }

  initializeApp() {
       this.platform.ready().then(() => {
       this.check();

      //Notifications
      if(this.isToggled == true){
      this.fcm.subscribeToTopic('all');
      this.fcm.getToken().then(token=>{
          console.log(token);
      })
      this.fcm.onNotification().subscribe(data=>{

        if(data.wasTapped){
                this.nav.setRoot(ArticledetailsPage, {x:data.newsid});

          console.log("Received in background");
        } else {
          console.log("Received in foreground");
        };
      })
      if(this.isToggled == true){
        this.fcm.subscribeToTopic('marketing');
      }

      else{
      this.fcm.unsubscribeFromTopic('marketing');
      }

      //end notifications.

      // Okay, so the platform is ready and our plugins are available.
      // Here you can do any higher level native things you might need.
      this.splashScreen.hide();
    });
  }



        notification(){
  this.nav.push(NotificationPage);
  }

public notify() {
  console.log("Toggled: "+ this.isToggled); 
  this.nativeStorage.setItem('toggle', {property: this.isToggled, anotherProperty: 'anotherValue'})
  .then(
    () => console.log('Stored item!'),
    error => console.error('Error storing item', error)
  );

}

check(){
  this.nativeStorage.getItem('toggle')
  .then(
    (data) => {
    console.log(data.property),
    this.isToggled = data.property;
    console.log(this.isToggled);
    }
  );
}
}

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